The degree of animal movement of human remains is a function of corpse size and decomposition, position, degree of burial, presence of clothing or wrapping, relative size and strength of the scavenger, season, terrain, topography, and vegetation (Haglund, 1997a). Body movement, often indicated by drag marks or disturbed ground cover, occurs in stages between rest places or food caches; these locations may be marked by discoloration from body fluid seepage. Larger animals, able to drag an entire human corpse, often move it some distance before covering it with debris or burying it in a shallow grave. Heavily gnawed or chewed bones are likely to have been first carried off from the original body location.

Skeletal remains are usually found within 100 metres of the primary deposition site, but some pieces may be dragged as far away as 300 metres (Haglund, 1997a). Evidence is most likely located along animal trails and paths between primary body deposition and other recovery sites, but these trajectories might not be straight because of interim rest sites (Keppel & Birnes, 1995). Terrain, inclines, and sedimentation also influence the scatter pattern (Haglund, 1997b).

Teeth and bone fragments are often found in animal scats; their analysis can assist in species identification and determination of animal territory and movement patterns. Coyote ranges vary from an average of 3.2 kilometres in forested areas to 16.1 kilometres in open landscapes (Haglund, 1997a). Understanding faunal activity is an important step in establishing the evidence search area (Murad, 1997).

8.1.6Learning and Displacement

The criminal hunt is influenced by both internal and external factors. Serial offenders gain knowledge with each new crime and they often learn from their experiences, successes, and failures, avoiding mistakes and repeating successful tactics (Cusson, 1993; Warren et al., 1995). Criminal development also results from education, changes in lifestyle, increased “professionalism,” new associates, and disorder progression. Media disclosures and certain investigative strategies, particularly patrol saturation tactics, may create spatial and temporal displacement, altering the geographic behaviour of the offender to the point that apprehension is hindered or delayed.

After the media reported fibre evidence had been recovered from victims’ bodies during the investigation of the Atlanta Child Murders, Wayne Williams changed his dumping grounds from remote roads and wooded areas to local rivers (Douglas & Olshaker, 1995; Glover & Witham, 1989). By disposing of unclothed bodies in this fashion he hoped that any physical evidence would be washed off by the water. The geography of Atlanta’s rivers is markedly different from that of its roads and woods, therefore this change in M.O. led to a shift in the geographic pattern of the crime sites (see Dettlinger & Prugh,

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1983). After the publication by the Victoria Times-Colonist of an unofficial profile on a dangerous serial arsonist in which a psychologist stated the offender was operating in his own neighbourhood, Manley Eng targeted a building on the other side of Saanich, British Columbia, removed from all his previous fires. And when New York papers wondered if the Son of Sam would continue his pattern and strike in each of the City’s boroughs, David Berkowitz responded accordingly (Ressler & Shachtman, 1992).

Displacement is a change in an offender’s pattern of behaviour as the result of crime prevention efforts, community wariness, or police investigative strategies. While displacement is by no means a certain result, it is more likely to occur with strongly motivated criminals such as sex offenders. There are five possible outcomes of displacement typically discussed in the literature: (1) spatial (geographic or territorial); (2) temporal; (3) target; (4) tactical; and (5) functional (activity) (Reppetto, 1976). Spatial displacement is the main concern for geographic profiling, but the other forms of displacement can also alter target patterns because of victim backcloth influences. Davies & Dale (1995b) found evidence for spatial, temporal, and tactical displacement in their study of British serial rapists.

Geographic or spatial displacement results when an offender relocates his or her criminal activity in response to a perceived increase in the risk of apprehension or reduction in opportunity (Gabor, 1978; Lowman, 1986). This geographic shift can be on a neighbourhood, metropolitan, or regional scale. Spatial displacement also involves a change in the type of place targeted within the same general area (e.g., from a downtown prostitution stroll to a downtown nightclub district). Some offenders move of their own accord and commit crimes in a new neighbourhood, but this is not characterized as displacement because the change resulted from something other than police or community action.

Temporal displacement results when an offender shifts his or her criminal activity to a different time period in response to a perceived modification in risk or opportunity environments. The shift is to a period (e.g., time of day, day of week, etc.) when acceptable risk and target availability levels exist. This may involve an extended period of offender inactivity, ranging from weeks to years, known as remission. Remission can also result from episodic behaviour on the part of the offender; in such cases, the temporal patterning of the crimes is the result of internal psychological factors, and not external influences. It is not uncommon for a criminal to appear to have gone into remission, when in reality he or she has only moved to another area — perhaps as the result of spatial displacement. Communication difficulties and linkage blindness then prevent the crimes in the new jurisdiction from being linked to the previous ones.

© 2000 by CRC Press LLC